A stacking scheme for solution-processable electrochromic polymers is presented with the integration of direct photolithography patterning to realize full colors, layered textures, and controllable color switching.
Conjugated polymers can be electrochemically bleached
to achieve
colored-to-transmissive electrochromic switching. This work presents
a side chain engineering approach to enhance colored state absorptivity
of an electrochromic polymer, while maintaining high transmissivity
in the bleached state. A series of dioxythiophene copolymers with
systematic variations in their branched alkyl side chains have been
used to understand side chain influence on solubility, aggregation,
film morphology and optical constants. By increasing the chromophore
density through an appropriate choice of side chains, the absorption
coefficient of the colored polymer can be improved by almost 50%,
with minimal influence on bleached-state absorption coefficients over
the visible region. As such, solution-processed films of high absorbance
can be prepared using thin polymer layers to achieve fast electrochromic
switching and highly transmissive bleached states. Under optimized
conditions, optical contrasts nearing 80% can be reached at the wavelength
of maximum absorbance, among the highest reported for solution-processed,
cathodically coloring electrochromic polymers. The improved absorption
coefficients are especially useful in enhancing the electrochromic
performance in the low transmittance regime (colored state transmittance
<20%), providing useful insights for designing high contrast electrochromic
materials.
Subclavian stenosis is a highly prevalent and underrecognized clinical entity. In patients with a history of coronary artery bypass grafting utilizing a left internal mammary artery, subclavian artery stenosis can cause coronary-subclavian steal, leading to myocardial ischemia. Traditionally, this has been treated surgically with a vascular bypass operation. Two cases of coronary-subclavian steal syndrome are presented, 1 treated percutaneously with angioplasty and stent, and 1 treated with a combined endovascular-surgical procedure.
Bioprosthetic tricuspid valve stenosis as a sequela of infective endocarditis is extremely rare. We describe the case of a 29-year-old male patient with a history of intravenous drug use and two previous bioprosthetic tricuspid valve placements who presented with recurrent endocarditis and severe tricuspid stenosis. He was deemed extremely high risk for redo valve replacement surgery. Intracardiac ultrasound-guided balloon valvuloplasty was performed with good clinical outcome. We believe that interventional treatment of prosthetic valvular stenosis in the setting of endocarditis is a reasonable therapeutic choice when open surgical repair is associated with prohibitively high mortality. This can be performed either as destination therapy or as a bridge to valve replacement. The use of intracardiac ultrasound provided additive information to that obtained by transthoracic and transesophageal echocardiography. V C 2014 Wiley Periodicals, Inc.
Polyelectrolytes, a class of polymer with ionized functional groups in their repeating units, are widely used in various applications. Many ionized groups have been incorporated into polyelectrolytes, but aromatic anions are rarely investigated. Here, we first successfully incorporate a stable tetracyanocyclopentadienide (TCCp) aromatic anion into polynorbornene (PNb)-based electrolytes (PNb-TCCp) through ring-opening metathesis polymerization (ROMP) with controllable molecular weight and low polydispersity. PNb-TCCp shows a high ionic conductivity of 4.5 × 10 −5 S/cm in thin films. Due to its highly stable aromatic anion groups and favorable interactions with aromatic cations, it could improve thermal stability of doped conjugated polymers. Pairing with doped poly(3,4ethylenedioxythiophene) (PEDOT) through salt metathesis, the generated poly ion complex PEDOT:PNb-TCCp retains its conductivity up to 180 °C.
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